S-20 Vertical Boiler

The S-20 boilers have used both 3/8" (R_1277) as well as 1/2" (R_460) safety valves, so it is recommended that you check your size first, prior to purchasing. The old version with male threads on the top for the venting pipe are out-of-production, so no longer available. Additionally both the capillary type (R_424) as well as a contact type (R_1006) type thermostats were used, depending on the year of manufacture, the R_424 eventually replacing older versions that used the R_1006. Most of the metal components and pipes are also out-of-production.